Anharmonic contributions in real RF linear quadrupole traps

• Published in: International journal of mass spectrometry 2010-02, Vol.290 (2), p.100-105
• Main Authors: Pedregosa, J., Champenois, C., Houssin, M., Knoop, M.
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Anharmonic term; Atomic Physics; Chemical Sciences; Harmonic field; Instrumentation and Detectors; Ion trap mass spectrometer; Nonlinear resonance; Physics; Quadrupole linear trap
• ISSN: 1387-3806; 1873-2798
• DOI: 10.1016/j.ijms.2009.12.009

The presence of anharmonic terms in the radiofrequency potential in a radiofrequency quadrupole linear ion trap limits the total number of stored ions. In this paper, we have studied the anharmonic content of the trapping potential for different implementations of a quadrupole trap, searching for the geometry best suited for the trapping of large ion clouds. As a result of the study, an alternative geometry is proposed which represents a compromise between simplicity and quality of the trapping field. The radiofrequency quadrupole linear ion trap is a widely used device in physics and chemistry. When used for trapping of large ion clouds, the presence of anharmonic terms in the radiofrequency potential limits the total number of stored ions. In this paper, we have studied the anharmonic content of the trapping potential for different implementations of a quadrupole trap, searching for the geometry best suited for the trapping of large ion clouds. This is done by calculating the potential of a real trap using SIMION8.0, followed by a fit, which allows us to obtain the evolution of anharmonic terms for a large part of the inner volume of the trap.